CN101308170A - Active electric current test technology - Google Patents
Active electric current test technology Download PDFInfo
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- CN101308170A CN101308170A CNA2007100738133A CN200710073813A CN101308170A CN 101308170 A CN101308170 A CN 101308170A CN A2007100738133 A CNA2007100738133 A CN A2007100738133A CN 200710073813 A CN200710073813 A CN 200710073813A CN 101308170 A CN101308170 A CN 101308170A
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Abstract
Disclosed is an active current testing technique, which uses a distributed resistor in a tested circuit as a current detecting resistor, and connects a voltage measuring tool and a current source to the current detecting resistor in parallel. The technique adopts basic testing principles of Ohm law and Kirchhoff law in electronics. When in test, firstly the current source is turned off to test the voltage on the current detecting resistor; and secondly, the current source is turned on to retest the voltage on the current detecting resistor. The magnitude of the tested current can be calculated according to the magnitude of voltage and current source in the two tests. The technique has a particular case that the direction and magnitude of the current source are changed, therefore the voltage of the distributed resistor is zero and the test to micro-current is more convenient. Adopting the technique can test current as testing voltage. The present well-known current detecting resistor method for testing current can actually be seen as the particular case in the technique that the magnitude of the current detecting resistor is given and the current source is zero.
Description
Affiliated technical field
The present invention relates to electric current test technology in a kind of electronic technology, especially the technology of measuring current is not come in the testing tool into tested loop of connecting.
Background technology
At present, known main electric current test technology mainly contains several:
One: the moving-coil reometer;
Two: inspection leakage resistance method is connected in series to the inspection leakage resistance in the current return size of measuring voltage reflection electric current;
Three: utilize electromagnetic induction principle, detect the size in the magnetic field of tested electric current, measure the size of electric current;
For the technology of first kind moving-coil reometer, be the most ancient electric current test technology, come measuring current by the way that the coil generation electromagnetic force that is connected in series in the current return deflects pointer.Owing to reasons such as low precisions, seldom used now.
For the second class technology, its principle is that the inspection leakage resistance of a known numeric value is connected in series in the current return, reflects the size of electric current by the terminal voltage of measuring the inspection leakage resistance.The defective of this method is to disconnect measured loop, and surveying instrument or current detection sensor are concatenated into the inside, just can measure then.In actual the use, need cut off circuit or place in advance current sensor, not only use inconvenience, and a lot of occasion is brought very mistake and interference owing to seal in testing tool.If set in advance the method for current sensor in the employing loop, for the circuit of more complicated a lot of inspection leakage resistances need be set, not only cost increases, and it is excessive to make trouble and volume.
Use the reometer of this class technology of employing, carry out the measurement of electric current, need sever processing a lot of circuits, not only pretty troublesome, inconvenient operation, and have a strong impact on the reliable of circuit.
For three types of technology, relatively be typically pincers type reometer, can be with the lead that stayed of testing clamp being clamped tested electric current, the electromagnetic field size that detects in the testing clamp is measured electric current.This technological deficiency is to measure alternating current, for the overwhelming majority's light current electronic product, the situation that can be clamped the electric wire in the testing clamp is often arranged unlikely, and therefore this method of testing also is restricted to the scope use of forceful electric power substantially.
Summary of the invention
The present invention proposes a kind of new current test method, does not need testing tool is connected in series in the tested loop, only need come measuring current just passable as working voltage table test voltage.
Ultimate principle of the present invention is Ohm law and Kirchhoff's law.
Common conductor all has resistance, and electric current flows through this resistance will produce voltage.If this resistance is known dimensions, test out the both end voltage of this resistance so, just can calculate the size of electric current according to Ohm law.Estimated current test instrumentation major part adopts this way.Because must know the size that detects resistance, so present testing current instrument all adopts the inspection leakage resistance of built-in known dimensions, and is linked to this resistance string in the test loop, the size that reflects tested electric current of the terminal voltage by measuring this resistance.
One of key of the present invention is the distributed resistance that directly utilizes in the tested circuit, it can be flow through conductor resistance on the path of tested electric current, it also can be the equivalent resistance of other electron devices, for example cover the copper cabling on the circuit board plate, this unknown distributed resistance is used as the inspection leakage resistance.Measure the voltage at these resistance two ends, can be called Vx
1, note and prepare to use.
Two of key of the present invention is that this resistance is injected a known electric current I from two test points
0, measure second voltage Vx simultaneously
2According to Kirchhoff's law and Ohm law, use Vx
1, Vx
2, I
0These given datas can calculate distributed resistance and just examine leakage resistance and size tested electric current.
Like this, do not need the inspection leakage resistance is connected in series to the size of current that just can test out tested loop in the circuit.
The invention has the beneficial effects as follows and to be made into the testing current instrument according to present principles, come measuring current, improve the ease of use and the work efficiency of reometer greatly, reduce interference simultaneously tested circuit as test voltage.
Description of drawings
The present invention is further described below in conjunction with accompanying drawing.
Fig. 1 is the equivalent schematic diagram of known a kind of testing current.
Fig. 2 is the equivalent schematic diagram of testing current of the present invention.
Among Fig. 1, the resistance in the tested loop of Rx equivalence, Ix flows through the tested electric current of Rx, the Vm voltage table, A, B, C, D, E, F are circuit node.
Among Fig. 2, the resistance in the tested loop of Rx equivalence, Ix flows through the tested electric current of Rx, the Vm voltage table, the Ic current source, A, B, C, D, E, F are circuit node.
According to electronic technology theory and method, think that the impedance of Vm voltage table is infinity, the internal resistance of Ic current source is infinitely great, ignores the influence of these two parameters to circuit analysis.Current source in the side circuit also can be a voltage source that enough imperial palace resistance is arranged, and is only just passable otherwise influence measuring accuracy.
Known electric current test technology is the size that must know Rx, therefore takes to be provided with the resistance of known dimensions in reometer, by reading the numerical value V of Vm voltage table, according to Ohm law
Ix＝V/Rx
Just can obtain the size of tested electric current.
As can be seen from Figure 2, Duo a current source Ic than known method in the method for testing of the present invention.Method test process of the present invention is:
The first step: current source Ic closes earlier, and just its generation electric current I 0 is 0, and this time, the equivalent current of circuit and Fig. 1 was identical, and is same by reading the numerical value Vx1 of Vm voltage table.The present invention does not need to know the size of Rx, just do not need to be linked to tested circuit the inside detecting resistance string, so Rx also is unknown.In the actual measurement, can use distributed resistance to be used as examining leakage resistance.Have according to Ohm law:
Vx1＝Ix*Rx
Second step: open current source Ic, make it produce the controlled current known I of numerical value
0, the electric current that detect on the resistance R x this time is exactly I
0+ Ix, and according to Kirchhoff's law, the electric current that flows out tested resistance remains Ix not to be changed.Read the numerical value Vx2 of Vm voltage table this time, have according to Ohm law:
Vx2＝(I0+Ix)*Rx
The equation that merges the first step is eliminated the Rx of position, can solve:
Can see, all be numerical value known or that measured in the formula, calculates and just can obtain the size of tested electric current I x, and have nothing to do with Rx.
Comparison diagram 1 and Fig. 2 can be easy to find out that known inspection leakage resistance method of testing is actual to be I among the present invention
0It is a zero special case.
Current source I in the variation diagram 2
0Direction, can also obtain the another one special case, if be exactly I
0With the direction of tested electric current I x equal and opposite in direction on the contrary mutually, can cause Vx2 is 0, and the computing formula above this time is just inapplicable, but but can directly obtain the size of tested electric current I x, equals I exactly
0, and current opposite in direction.This special case also is of great use, and when tested electric current is very little, and hot-tempered psophometric voltage can improve the precision of measurement result bigger the time.The similar electric bridge of this measuring process, and reach when measuring numerical value, inspection leakage resistance both end voltage is zero, as superconductor, therefore can be called superconductive bridge.
The present invention need be to tested circuit injection current, and initiatively and can control, so claim the active electric current method of testing.
Claims (4)
1. active electric current test technology is characterized in that: voltage tester instrument and current source parallel connection, and then be parallel on the inspection leakage resistance that tested electric current flows through and measure electric current.
2. active electric current test technology according to claim 1 is characterized in that: only need be parallel to voltage measurement table and current source doublet on the inspection leakage resistance that tested electric current flows through just passablely in the measurement, not need to disconnect tested loop.
3. active electric current test technology according to claim 1 is characterized in that: need in the measurement inspection leakage resistance injection current.
4. active electric current test technology according to claim 1, it is characterized in that: a special case is numerical value and the direction that changes current source in the measurement, voltage tester instrument reading up to parallel connection is zero, and then the numerical value of current source is just identical with tested size of current, and direction is opposite.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNA2007100738133A CN101308170A (en) | 2007-05-18 | 2007-05-18 | Active electric current test technology |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNA2007100738133A CN101308170A (en) | 2007-05-18 | 2007-05-18 | Active electric current test technology |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN101308170A true CN101308170A (en) | 2008-11-19 |
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ID=40124725
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CNA2007100738133A Pending CN101308170A (en) | 2007-05-18 | 2007-05-18 | Active electric current test technology |
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Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103217567A (en) * | 2013-04-19 | 2013-07-24 | 华为技术有限公司 | Current detection method and power detection circuit |
| CN106531580A (en) * | 2016-11-09 | 2017-03-22 | 首瑞（天津）电气设备有限公司 | Micro breaker and distribution system |
| CN106771487A (en) * | 2016-12-22 | 2017-05-31 | 上海传英信息技术有限公司 | The method of measuring instrument, the method for measurement electric current and measurement mobile phone charging current |
| CN107976568A (en) * | 2016-10-24 | 2018-05-01 | 力诚仪器股份有限公司 | A kind of current measuring method and its system |
| CN108802476A (en) * | 2018-06-13 | 2018-11-13 | 贵州电网有限责任公司 | A kind of DC current transformer and its current test method |
| CN110488084A (en) * | 2019-09-26 | 2019-11-22 | 京信通信***（中国）有限公司 | Pcb board branch current detection device and system |
| CN113804948A (en) * | 2021-10-15 | 2021-12-17 | 无锡江南计算技术研究所 | Current sampling method suitable for multi-path parallel circuit |
-
2007
- 2007-05-18 CN CNA2007100738133A patent/CN101308170A/en active Pending
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103217567A (en) * | 2013-04-19 | 2013-07-24 | 华为技术有限公司 | Current detection method and power detection circuit |
| CN107976568A (en) * | 2016-10-24 | 2018-05-01 | 力诚仪器股份有限公司 | A kind of current measuring method and its system |
| CN106531580A (en) * | 2016-11-09 | 2017-03-22 | 首瑞（天津）电气设备有限公司 | Micro breaker and distribution system |
| CN106771487A (en) * | 2016-12-22 | 2017-05-31 | 上海传英信息技术有限公司 | The method of measuring instrument, the method for measurement electric current and measurement mobile phone charging current |
| CN108802476A (en) * | 2018-06-13 | 2018-11-13 | 贵州电网有限责任公司 | A kind of DC current transformer and its current test method |
| CN110488084A (en) * | 2019-09-26 | 2019-11-22 | 京信通信***（中国）有限公司 | Pcb board branch current detection device and system |
| CN113804948A (en) * | 2021-10-15 | 2021-12-17 | 无锡江南计算技术研究所 | Current sampling method suitable for multi-path parallel circuit |
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| PB01 | Publication | ||
| C02 | Deemed withdrawal of patent application after publication (patent law 2001) | ||
| WD01 | Invention patent application deemed withdrawn after publication |
Open date: 20081119 |